Kinetic Analysis of Oxygen Dissolution by Bubble-attaching Electrodes

Bubble-attaching electrodes have been constructed to determine the kinetics of the oxygen dissolution to an aqueous solution. Since the four-electron reduction of oxygen is accelerated by a multi-copper oxidase modified porous gold electrode, the mass-transfer process of oxygen in the solution is the rate-determining step. The bubble attached electrode provides a steady-state oxygen reduction current. The current when the bubble has been detached from the electrode surface is highly reproducible. The dissolution-rate constants of the buffer solutions are estimated from the current by a comparison between the experimental results and the numerical simulation results. The increase in the concentration of the buffer solution increases the dissolution rate constants of oxygen while decreasing the saturated concentration and diffusion coefficient of oxygen.